Trajectory Analysis in a Gyrotron Electron–Optical System with Allowance for the Cathode Surface Roughness

We propose a method for considering the spread of initial electron velocities caused by the roughness of the cathode surface while performing a three-dimensional trajectory analysis in the gyrotron electron–optical system. The effect of the size of roughness on the velocity characteristics of the electron beam entering the gyrotron cavity with a frequency of 74.2 GHz and an output power of approximately 100 kW was determined in the simulations. Comparison of simulation data with experimental results showed that the average size of cathode inhomogeneities for this gyrotron is approximately 14 μm for the model of a cathode with regular hemispheres on its surface.